I have a samsung galaxy tab 4, i have already changed the download location to sd card, but i want to download an app and it says it can't be downloaded on the sd card, that it must be on the device. how can i revert it to download on the device, without taking the sd card out? Help its annoying to take out the otter box cover out, everytime.
You probably have just changed the preferred install location (I'm not aware of a setting that enforces a location for app install). So IMHO you don't need worry, simply install that app.
Developers must declare their app's preferred install location in the
Manifest of the app. There they basically have 3 choices: internal storage, external storage, let-the-OS-decide. On the OS side, again there's a corresponding setting: internal, external, default (usually internal). You altered the latter to "external" I assume.
Now what happens when you've set the OS side to "external"? Depends on what the
Manifest of the app-to-be-installed says: if it says "let-the-OS-decide", things are clear: the app goes there (in your case, the external storage AKA SD card). Everything else overrides the OS-side setting: If an app offers services/widgets, it must go to internal storage, hence the developer will declare such – and the OS will obey.
So: No need to change anything. If the app must be installed to internal storage, the dev should have taken care for that in the app's
Manifest. If you're still running into trouble, see my answer here on how to change the default.
Some apps need to be installed on non-unmountable device-memory because they depend on an app-s service that must run continuously without beeing stopped if sd is unmounted/ejected.
The developper of the app can declare that the app must be installed on device memory.
You can try to install the app in device-s memory and later move it to sd-card via settings/app/move to sd.
If the developper does not want the app to be installed on sd this option is not available.
You can also try to use the android app app2sd for this.